Brittle materials fail due to maximum shear stress rather than principal stresses.

Determine the casting-position modification factor, ψt, for a rectangular beam with b = 17 in. and d = 23 in., four epoxy-coated No. 7 Grade 60 tension-reinforcement bars placed in the bottom of the beam, and No. 3 Grade 60 stirrups located every 12 in. along the span. Assume 8,000-psi lightweight concrete and a clear cover of 1.5 in.

A 125-mm-long beam supports a load of P = 48 N at midspan. The cross section is rectangular with width b = 29 mm and height h = 60 mm. Determine the magnitude of the horizontal shear stress at the centroid of the cross section.

Researchers studying reinforced concrete have considered a mechanical explanation of Vs to be the Holy Grail.

Determine the transverse reinforcement index, Ktr, for a rectangular beam with b = 17 in. and d = 23 in., five galvanized No. 9 Grade 60 tension-reinforcement bars placed in the top of the beam, and No. 3 Grade 40 stirrups located every 6 in. along the span. Assume 7,000-psi lightweight concrete and a clear cover of 2 in.

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Bond stress values do not vary from point to point between cracks.

Use ACI 318-14 Table 25.4.2.2 to determine the development length for the straight tension bars (no hooks) in a rectangular beam with b = 16 in. and d = 22 in., four uncoated No. 9 Grade 60 bars placed in the top of the beam, and No. 4 Grade 60 stirrups located every 10 in. along the span. Assume 4,000-psi lightweight concrete and a clear cover of 2 in.

Stirrups do not preventing inclined cracks from forming.

The easiest way to test the bond strength of bars in a laboratory is by the pull-out test.